notes/Notes/NoteViewController.swift

//
//  NoteViewController.swift
//  Notes
//
//  Created by Laurent Morvillier on 04/09/2022.
//

import Foundation
import UIKit
import CoreData

class NoteViewController : UIViewController, UITextViewDelegate {
    
    var note: Note? = nil
    
    @IBOutlet weak var textView: UITextView!

    @IBOutlet weak var textViewBottomConstraint: NSLayoutConstraint!
    
    fileprivate weak var _lastEditLabel: UILabel?
    
    // MARK: -
    
    override func viewDidLoad() {
        super.viewDidLoad()

        let shareButton = UIBarButtonItem(barButtonSystemItem: .action, target: self, action: #selector(shareHandler))
        let addButton = UIBarButtonItem(barButtonSystemItem: .add, target: self, action: #selector(addHandler))
        self.navigationItem.rightBarButtonItems = [addButton, shareButton]
        
        self._loadLastNote()
        
        self.textView.font = UIFont.systemFont(ofSize: 18.0, weight: .regular)
        self.textView.delegate = self
        self.textView.inputAccessoryView = self._inputAccessoryView()
        
        self._updateLastEdit()
        
        /// Store notifications
        
        print("REGISTER")
        
        NotificationCenter.default.addObserver(self, selector: #selector(self._storeRemoteChange(notification:)), name: NSPersistentCloudKitContainer.eventChangedNotification, object: nil)
        
        /// Keyboard notifications
        
        NotificationCenter.default.addObserver(
            self,
            selector: #selector(keyboardDidShow(notification:)),
            name: UIResponder.keyboardDidShowNotification,
            object: nil
        )

        NotificationCenter.default.addObserver(
            self,
            selector: #selector(keyboardWillHide),
            name: UIResponder.keyboardWillHideNotification,
            object: nil
        )
        
    }
    
    fileprivate func _loadLastNote() {
        
        let request = Note.fetchRequest()
        request.sortDescriptors = [NSSortDescriptor(key: "lastEditDate", ascending: false)]
        
        do {
            let notes = try AppDelegate.viewContext.fetch(request)
            
            print("notes in store : \(notes.count)")
            
            self.note = notes.first
            self.textView.text = self.note?.content
        } catch {
            print("Fetch error = \(error)")
        }
        
    }
    
    @objc fileprivate func _storeRemoteChange(notification: Notification) {
        print("_storeRemoteChange...")
        DispatchQueue.main.async {
            self._loadLastNote()
        }
    }
    
    func textViewDidChange(_ textView: UITextView) {
        PreferencesStorage.main.requestStorage(filename: "main.txt", content: textView.text)
        
        let note: Note
        if let n = self.note {
            note = n
        } else {
            note = Note(context: AppDelegate.viewContext)
            self.note = note
        }
        
        CoreDataStorage.main.requestStorage(note: note, content: textView.text)
        
        self._updateLastEdit()
    }
    
    fileprivate func _updateLastEdit() {
        
        if let date = self.note?.lastEditDate {
            let formattedDate: String = date.formatted()
            self._lastEditLabel?.text = "last edit: \(formattedDate)"
        }
    }
    
    fileprivate func _inputAccessoryView() -> UIView {
        
        let toolbar: UIToolbar = UIToolbar(frame: CGRect(x: 0, y: 0, width: 333, height: 44.0))
        
        let lastEditLabel = UILabel(frame: CGRect(x: 0, y: 0, width: 280, height: 44))
        lastEditLabel.textColor = UIColor.gray
        let lastEditButtonItem = UIBarButtonItem(customView: lastEditLabel)
        self._lastEditLabel = lastEditLabel
        
        let flexButton = UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: nil, action: nil)
        let dismissButton = UIBarButtonItem(image: UIImage(systemName: "checkmark"), style: .done, target: self, action: #selector(dismissKeyboard))
        toolbar.items = [lastEditButtonItem, flexButton, dismissButton]
        
        let swipeDown = UISwipeGestureRecognizer(target: self, action: #selector(dismissKeyboard))
        swipeDown.direction = .down
        toolbar.addGestureRecognizer(swipeDown)
        
        return toolbar
    }
    
    // MARK: - Keyboard
    
    @objc func dismissKeyboard() {
        self.textView.resignFirstResponder()
    }
    
    @objc func keyboardDidShow(notification: NSNotification) {
        guard let keyboardRect = notification
            .userInfo?[UIResponder.keyboardFrameEndUserInfoKey]
            as? NSValue else { return }
        let frameKeyboard = keyboardRect.cgRectValue
        
        self.textViewBottomConstraint.constant = frameKeyboard.size.height
    }

    @objc func keyboardWillHide() {
        self.textViewBottomConstraint.constant = 0.0
    }
    
    // MARK: - Business
    
    @objc func shareHandler() {
        
        guard let text = self.textView.text else {
            return
        }
        
        let activityViewController = UIActivityViewController(activityItems: [text], applicationActivities: nil)
        self.present(activityViewController, animated: true)
    }
    
    @objc func addHandler() {
        
    }

    deinit {
        NotificationCenter.default.removeObserver(self)
    }
    
}